Catalytic converters



July 11, 1933. A. o. JAEGER CATALYTIC CONVERTER 2 sheets-sheet 1 FiledMay 31, 1930 INVENTOR fuel/ans 0. Jaeyer ATTORNEY July 11, 1933. A. oJAEGER CATALYTIC CONVERTER Filed May 51, 1930 2 Sheets-Sheet 2 animatorUITED STAES PTEN'F OFFICE ALPHONS O. JAEGER, OF. MOUNT LEBANON,PENNSYLVANIA, ASSIGNOR, BY MESNE AS- SIGNMENTS, TO THE SELDEN RESEARCH &ENGINEERING CORPORATION, OF PITTS- BURGH, PENNSYLVANIA, A CORPORATION OFDELAWARE CATALYTIC CONVERTERS.

Application filed May 31,

action.

Converters or" this type are usually constructed after the same fashionas a fire tube boiler; that is to say the catalyst tubes are welded orexpanded into tube sheets which are rigidly fastened to the convertershell. In carrying out reactions which take place at relatively lowtemperatures water or salt solutions have been used as bath material,but for reactions which take place at more elevated temperatures it hasbeen necessary to use metals, alloys or mixtures of salts in the moltenstate.

in the development of converters of the type described for hightemperature reactions, and even for reactions that take place atcomparatively low temperatures much i ditiiculty has been experienced inpreventing the leaks that result from warping of the tubes andtubesheets. This warping is main ly the result of the unequallongitudinal expansion of the shell and tubes and the enormous stressesresulting, since in the ordinary boiler type construction there has beenno means of compensating for this movement. It has been the custom touse extremely heavy tubesheets and both welding and expansion of thetubes, which has added greatly to the cost of the apparatus but has notentirely solved the problem.

I have now found that this difficulty can be overcome by providing theconverter with a floating upper tubesheet, that is to say one in whichthe weight of the tubes, the upper tubesheet, and the uppersuperstructure of the converter rests entirely on the lower tubesheet.Any movement due to expansion or contraction is taken up by flexibleconnections between the superstructure and the converter shell. In thisway the converter is made gas-tight and permits the use of mercury,mercury alloys, salt solutions and molten salt mixtures which would beoxi- 1930. Serial No. 458,010.

dized in contact with the air or which would give olt' poisonous orirritating vapors in operation. By this construction converters eitherof the boiling or non-boiling bath type,

or of the combined boiling and non-boiling 65 bath type can be developedhaving all the advantages of those of the prior art with the addedadvantage that the tendency to warp is entirely overcome,

Converters constructed according to the so present invention areapplicable to the most varied types of catalytic reactions, such asoxidations of organic compounds to intermediate products, for examplethe oxidation of bcnzole to inaleic acid, toluol and the varies oussubstituted toluols to the corresponding aldehydes and acids,naphthalene to phthalic anhydride, anthracenc-to anthraquinone,acenaphthene to naphthalic anhydride, fluorene to iiuorenone and thelike; reactions in which v an undesired impurity is burned out such asthe purification of crude anthracene, crude naphthalene or coal tarammonia and oxidations of mixtures of organic compounds with or withoutcatalytic purification. Reduc- 75 tions and hydrogenations, such as thereduction of nitrobenzene to aniline, aldehydes and ketones to alcohols,hydrocarbons such as naphthalene to tetraline and decaline, phthalicanhydride to phthalide and the like; 3@ and splitting reactions such asthe production of benzoic acid from phthalic anhydride can also becarried out. The apparatus is also suitable for inorganic reactions,such. as the oxidation of sulfur dioxide to sulfur 35 trioxide, theoxidation of ammonia to oxides of nitrogen, and the production ofhydrocyanic acid from carbon monoxide and ammonia.

In the accompanying drawings representative types of converter have beenillustrated to which the features of the present invention have beenapplied. It is to be understood that the specific know features of theseconverters do not in themselves form any part 95 of the presentinvention and that in its broad aspects the invention can be applied toany converter of the boiling or non-boiling bath type, although certainadvantages are to be obtained by the combination of the flexible m0construction with known features of the converters shown and areincluded in the invention in its more specific aspects.

In the drawings:

Fig. 1 is a vertical section through a bath converter of the non-boilingor sensible heat type to which the flexible tubesheet constructron hasbeen applied;

Fig. 2 is a detail of the flexible connections shown in Fig. 1;

Fig. 3 is a detail of a sli htly modified form of connection that canlie used under suitable conditions; and

Fig. 4.- is a vertical section through a converter of the boiling bathtype.

Referring to Fig. 1, the converter in its usual form consists of aconverter shell 1, provided with top and bottom pieces 2 and 3 and upperand lower tubesheees 4 and 5 between which extend catalyst tubes 6, theshell be ng provided with an outlet 8 at the lower portion thereof. Thelower tubesheet 5 is set lnto the converter shell in the usual manner,but the upper tubesheet 4 is welded to a circular flange 9 in which theinlet 7 is provided and to which is fastened the top piece 2, providedwith the safety flange 10. The entire superstructure, consisting of theupper tube-' sheel 4, the flange 9- and the top piece 2, is carried bythe tubes 6 so that any expansion or contraction of the tubes resultsonly 1n a raisin or lowering of the superstructure. In or er tOPlOVldG aclosed bath chamber, which is necessary where oxidizable bath materialis to be used or where it is desired to effect the temperature controlby a bolling bath, the converter shell 1 is extendedupwardly around theflange'9, and the connection between the two surfaces is effected by athin, pleated flange 11 of a flexible metal such as highly temperedsteel or bronze or the like. This connection may consist of as manypleats or folds as may be found desirable in practice, only one suchfold being shown on the drawin s. The inner edge of the pleated rin iswel ed or otherwise suitably fastened to t e circular flange 9 while theouter edge is fastened to the converter shell 1, thus affording aflexible and at the same time a gastight joint. In boiling bathconverters where gas pressures considerably higher than atmospheric areencountered, it is sometimes desirable to reenforce these welds byturning up the edges of the metal and surrounding the connections bymetallic bands which are shrunk on or otherwise suitably fastened. Suchreenforcements, however, are not usually necessary in ordinary practicesince the development of the modern alloy baths, Wl'llCll control thecatalyst temperatures irrespective of pressure by adjustment of thecomposition of the alloy, have practically done awa with the use of highpressures on a boiling bath.

It is to be understood that the invention is not limited to the use ofthe pleated rings 11, but on the contrary any suitable type ofconnection may be used. Another type of connection which has been founduseful under certain conditions is that shown in Fig. 3, in which atight joint is maintained by means of a packing ring 12. In thisconstruction the upper edge of the converter shell 1 is turned inwardyto form a horizontal flange 13, the inner edge of which fits looselyaround the circular flange 9 and supports the packing 12. The packing isretained in position by a vertical ring 14 that is welded to the uppersurface of. the horizontal flange 13, while the packing is maintainedunder suitable pressure by the floating ring 15 of angle ironconstruction that is retained above it by means of suitable bolts 16. Inthis manner a gas-tight construction is obtained which has at the sametime the advantage of being easily dismounted for purposes of cleaningor repair.

The-modification of Fig. 4 shows the application of the invention toconverters of the boiling bath type in which pressure may be applied tothe boiling liquid in order to vary its boiling point. In this type ofconverter it is necessary to provide a flexible coupling which will bemore or less balanced against the increased pressure used on the surfaceof the liquid, and consequently the flexible flanges are placed withinthe vapor space above the boiling bath. The bath chamber is made up ofthe lower tube sheet 25, which is of the usual construction, and theconverter shell 21, the upper portion of which is turned inwardly as at30 and extends downwardy for a short distance parallel to the outer partof the shell. The upper tubesheet 24 supports the circular flange 29,which in turn supports the top piece 22, as in Fig. '1 and the catalysttubes 26 are fastened into the upper and lower tube sheets in the usualmanner. The bath liquid, which may be mercury, mercury alloys, or anysimilar liquid having a suitable boiling point, surrounds the cataysttubes and during operation its vapors are condensed in the refluxcondensers 31 and returned to the bath, suitable pressure being appliedto the refluxes at 32 in any suitable manner. The flexible connectionbetween floating superstructure andthe converter shell 21 is effected bymeans of the flexible flanges 33, which flex outwardly into the vaporspace of the converter in response to any relative movement between theconverter shell 21 and the upper tube sheet 24. It will be noted thatthe pressure on the upper and lower portions of the pleated flange 33 isthe same, so that the metal of the flange is under compression while theconverter is in operation rather than under tension as in Fig. 1. Forthis reason the flange is able to stand much higher pressures than isthe case with the reverse construction, and as the relative movementbetween the two parts in question is very slight, no difliculty isexperienced in retaining a tight connection.

As a result of the flexible connection between the upper and lowerportions of the converter it is possible to use metal baths, eitherboiling or non-boiling, as temperature regulating media, which is not soeasily done when there is danger of leakage of poisonous vapors orexposure of the bath material to the air. The high heat conductivity andheat capacity of metallic baths make them much more desirable thannon-metalic substances and therefore produce great improvements in theoperation of catalytic converters.

The operation of converters constructed according to the presentinvention is no different from those of the ordinary tube sheetconstruction once they are running, but the flexibility is of greatassistance in starting and stopping the operation. Formerly it wasnecessary to use great care in heating up and cooling down theseconverters, for sudden changes would result in great internal stressesand warping both of the tubesheets and of the tubes. By the use of afloating tubesheet construction such as has been described theconverters can now be heated to operating temperatures in far less timeand can be cooled down as rapidly as desired without danger of leakage,and the flexible closure member permits the use of almost any desiredbath material.

lVhat is claimed as new is:

1. A catalytic rigid converter comprising a converter shell, a lowertubesheet set welding into said converter shell, catalyst tubessupporting an upper tubesheet, a superstructure above said upper tubesheet and provided with a gas inlet, and flexible means enclosing thespace between said superstructure and said converter shell.

2. A catalytic rigid converted comprising a converter shell, a lowertubesheet set into said converter shell and forming therewith a bathchamber, catalyst tubes set into said lower tube sheet and supporting anupper tube sheet, a bath liquid in said chamber which during operationof the converter must be completely shut off from the outside air andflexible means enclosing the space between said upper tube sheet andsaid eonverter shell.

Apparatus according to claim 2, in which at least one component of thebath liquid is mercury.

4. A catalytic rigid converter comprising a converter shell, a lowertube sheet set into said converter shell and forming therewith a bathchamber, catalyst tubes set into said lower tube sheet and supporting anupper tube sheet, reflux condensers in communication with the upperportion of said converter shell, a bath liquid in said bath chamber atleast one of the components of which is mercury, means for applyingpressure to the space above said bath liquid, and a flexible connectionbetween said upper tubesheet and said converter shell.

5. Apparatus according to claim 4, in which the closure includes a thinpleated flange of a flexible metal which is so disposed that pressurewithin the bath chamber is exerted on the outer portions of the pleats.

6. A catalytic rigid converter comprising a converter shell, a lowertubesheet set into said converter shell to form therewith a bathchamber, catalyst tubes set into the central portion of said lower tubesheet and supporting an upper tube sheet, a superstructure above saidupper tubesheet and provided with a gas inlet, at least one verticalbattle in said bath chamber between the converter shell and saidcatalyst tubes, and flexible means inclosing the space between saidsuperstructure and said converter shell.

Signed at Pittsburgh, Pennsylvania, this 26th day of May 1930.

ALPHONS O. JAEGER.

